The development of hydrogen and/or deuterium generation sources for fuels for lasers has obviated the need for high pressure storage facilities under cryogenic conditions.
After the development of hydrogen and/or deuterium generation sources for high purity laser fuels the needs were recognized for additional improvements such as chemical reactants capable of generating hydrogen or deuterium in higher yield and with higher purity as evidenced by the evolution of the art described below.
Compositions which generate hydrogen as disclosed in U.S. Pat. No. 3,666,672, "Hydrogen Generating Compositions", by Ralph H. Hiltz. Disclosed is an autogeneously combustible composition that liberates hydrogen on burning. The composition contains an alkali metal borohydride and a hydrazine sulfate in proportions such that there are between about 0.5 to 2 boron atoms for each nitrogen atom.
Another example of a prior art source for hydrogen generation is disclosed by Huskins et al in U.S. Pat. No. 3,940,474 wherein unsolvated aluminum hydride is decomposed by a heat source (e.g., a wire of about 80% nickel and 20% chromium with a predetermined diameter which is positioned in contact with the unsolvated aluminum hydride, and provided with a means for electrically heating the hydride to a decomposition temperature range from about 180.degree. C. to about 185.degree. C.) to provide hydrogen gas at a lower temperature.
Examples of prior art compositions for producing hydrogen or deuterium at about 600.degree. C.-700.degree. C. are disclosed by Ayers et al in U.S. Pat. No. 3,948,699. These compositions are based on complex metal boron compounds of the general formula M(BH.sub.4).sub.x or M(BD.sub.4).sub.x, (wherein M equals a metal and x equals the valence of the metal M; M is an alkali metal or an alkali earth metal; H is hydrogen, and D is deuterium) and metal oxides of the general formula Q.sub.2 O.sub.3 (wherein Q is a trivalent metal selected from iron, aluminum, gallium, cobalt, and indium) combined stoichiometrically.
Higher temperature hydrogen or deuterium (e.g., about 3000.degree. C.) production is disclosed by Ayers et al in U.S. Pat. No. 3,948,700. This patent discloses a storable solid propellant composition based on unsolvated aluminum deuteride or unsolvated aluminum hydride and ferric oxide which produces high temperature gases from a self-sustaining reaction, once started, by a heat source such as an electrically heated nickel-chromium ignition wire. The hydrogen or deuterium produced is acceptable for use in HF/DF and HCl chemical lasers, the gas dynamic laser (GDL), or a source of hot gases for reducing fuel.
Additional prior art is disclosed by Chew et al in U.S. Pat. No. 4,061,512 which relates to storable solid propellant compositions based on complex metal boron compounds of the general formula M(BH.sub.4).sub.x or M(BD.sub.4).sub.x (wherein M equals a metal and x equals the valence of the metal M; M is an alkali metal or an alkaline earth metal; H is hydrogen, and D is deuterium) and ammonium salts of the general formula (NH.sub.4).sub.n Y or deuteroammonium salts of the general formula (ND.sub.4).sub.n Y (wherein Y represents an anion with a total charge of n; N is nitrogen, H is hydrogen, and D is deuterium. The specified compounds combined stoichiometrically or in varying molar ratios produce hydrogen or deuterium that contains nitrogen as an inert diluent which is acceptable for use in HF/DF chemical lasers, the gas dynamic laser GDL, or as a source of hydrogen containing an inert diluent.
In recent disclosures by Chew et al in U.S. Pat. No. 4,157,927, a class of compounds known as amine-boranes and their derivatives are mixed with heat producing compounds such as lithium aluminum hydride or a mixture, such as NaBH.sub.4 /Fe.sub.2 O.sub.3 mixtures combined in definite proportions in a mixer or ball mill to produce a uniformly mixed powder. The mixed powder is then pressed into pellets and ignited to produce the hydrogen or deuterium as well as byproducts that are non-deactivating diluents. The oxide/borohydride or oxide/aluminohydride combination provides the thermal energy for decomposition of the amine borane.
Advantageous would be an all amine borane system for producing hydrogen in high yield. This would obviate the requirement of the oxide/borohydride or oxide/aluminohydride compound which provides the thermal energy for decomposition. Thus, on a weight percentage basis an all amine borane system would provide a higher hydrogen yield than the mixed system of the prior art.
An object of this invention is to provide an all amine borane source for high purity hydrogen or deuterium generation.
Another object of this invention is to provide an all amine borane system which serves as the thermal stimulus for decomposition of itself to yield high purity hydrogen or deuterium.
Still a further object of this invention is to provide a source for high purity hydrogen or deuterium generation in the form of a solid propellant composition that is an all amine borane system comprised of one amine borane compound which serves as the ignition source for itself as well as the ignition source for another high yielding hydrogen or deuterium amine borane compound with which the ignition source compound is combined.